But Gruber admits that Bimini and some of the other smaller islands need better amenities for visitors, whose spending is crucial to the local economy. It's a difficult balancing act: Development done right, gentle on the environment and drawing tourists in manageable numbers, can help protect sharks and their ecosystem, Gruber says. But too much development or environmentally unsound practices can destroy them.

As recently as 2002, plans were in motion to set aside five marine areas to preserve the economic and ecological lifeblood of the Bahamas, with Bimini rated as the highest priority. But a change in government put off the project, and there's been no movement toward protection, despite angry prodding and accusations of corruption. Instead, giant resorts such as the one being built on Bimini have grown up on several outer islands. "The government is selling off this environment, cheap," Gruber says. A staffer at the Bahamas tourism office didn't exactly disagree. "We are a young country," said Leonard Stuart, referring to the Bahamas' 1973 independence from Britain. "We have to learn our own lessons about our environment, and we'll probably make mistakes."

The ramifications could be costly. Tourism accounts for nearly half the gross national product of the Bahamas. Diving is a multimillion-dollar industry here, and sharks are an ever increasing draw. By Gruber's back-of-the-envelope estimate, a single live shark in healthy habitat is worth as much as $200,000 in tourism revenue over its lifetime. And sharks' ecological value is inestimable. Not only do they weed out sick and weak fish, leaving the fittest to breed, but as top predators they also keep other carnivores in check, preventing them from depleting the algae-eating fish that keep coral reefs healthy. Studies in the Caribbean have shown that where sharks are keystone species, their depletion could topple ancient food hierarchies and ultimately destroy the reefs.

It is a great and sad irony that over much of the world sharks are prized foremost for the nearly tasteless cartilage ribbons, or "noodles," that make up their fins and are the costly key ingredient in shark-fin soup. As many as 73 million sharks die annually for their fins, which command more than $300 a pound in Asian markets. The trade is illegal and cruelly wasteful—finners often slice off the fins and throw the sharks back to starve, drown, or be eaten alive—but it continues to grow.